Do you know -------- when there is a fire?

问题描述:

Do you know -------- when there is a fire?
Do you know -------- when there is a fire?
A.how to do B.what to do
C.what do D.how do

不管采不采纳,我的回答就在这里
这里选B
这里时考你语法的,不是要你从中文意思出发的
这里因为do 时及物动词,因此后面缺少了宾语,时缺了成分,那就又what 充当,what 既是连词,也时做do 的宾语
而A ,要改成how to do it 就对了